In SfTextBoxExt, “SuggestionPredicate” cannot be handled in application level but it can be invoked by writing the delegate for this. Therefore, we have prepared a sample with SfTextBoxExt in which we have assigned “SuggestionMode” property as “Custom” and written delegate named “Filter” to handle the filtering of SfTextBoxExt. Please refer the below sample and KB link for further details about Filtering concepts of SfTextBoxExt.